Specialized has upgraded it's gravel specific wheel range today with the launch of two new additions to the Terra wheel family.
The new Terra Aero CLX and Terra CLX III wheelsets are 'the fastest gravel wheel family ever built'. This update somewhat mirrors the overhaul of the Rapide road range, which came in late June last year.
The first of this new pair of wheels is the Terra Aero CLX, a new addition for the Terra range and a wheelset that the brand says prioritises gravel-specific aerodynamic performance and speed. The Terra Aero is going to be the showstopper on gravel race bikes in the future, in part thanks to its distinctive, wide, squared-off front rim profile, which we get into below.
The Terra CLX III is a lighter (very light in fact, but we'll get to that) and shallower wheelset that features similar rim width specs and tech to the Terra Aero, but is geared towards climbers and blending low weight with comfort and capability.
The storyline involving high-end gravel racing only getting faster and more competitive has influenced the design of these wheels. Roval says 'gravel racing now demands the same level of aero discipline historically reserved for WorldTour races'. It seems this is another development in the ongoing quest for off-road speed.
The Terra Aero CLX
Rim depth: F - 50mm / R - 45mm
Weight: 1340 grams
External width: 38.5mm
Internal width: 27mm
Price: TBC
The carbon fibre Terra Aero CLX wheels come with an aero claim from Roval: The wheels are claimed to be 5.84 watts faster than the Terra CLX wheels with a 45mm Tracer gravel tyre at 40kph, and it reads like the wheels have been optimised around the Specialized Tracer gravel tyres in general.
We don't have in-depth data or testing info to support this claim, but Roval has talked about its design and testing procedure at some length.
The front wheel rim is 50mm deep and the rear 45mm. They are designed for 35-60mm tyres and feature a hooked rim with bead hook widths of 5.38mm to help minimise pinch punctures.
Roval has also added carbon-bladed spokes by Arris, which it claims save 0.3-0.5 watts, the same as those found on the latest Rapide wheelsets, which save a claimed 96.6 grams. Despite the carbon spokes, there's a claimed 21.52% reduction in lateral stiffness for improved control in the rough stuff.
We have the topline dimensions and stats, but the shape of the Terra Aero is the key talking point, it's flat front rim shape is going to draw attention.
The Aero CLX uses a flat 'truncated aerofoil' rim shape; in essence, the part of the rim closest to the wheel's hub is flat and squared off. Roval is calling this a 'chopped aero speed shape' and says it tests like a 70mm front wheel, which I assume means it tests like a faster wheel.
Roval chose from over 300 digital rim shapes and used gravel-specific 'whole system' CFD testing that included the wheel and tyre in a Specialized Crux frame, plus wind tunnel testing to arrive at the final product.
The brand says the rim and Tracer gravel tyres work in tandem to smooth the airflow coming off the taller gravel tyre and make it fast. It doesn't mention the wheel's performance with any other gravel tyres, and tyre selection is a key choice for gravel racers.
We assume performance drops slightly with a different tyre or size, but it seems safe to say this is at least another competitor to the race-focused Zipp 303 XPLR SW rims, which use the fast and wide theory as well.
The Terra CLX III
Rim depth: 27mm
Weight: 1079 grams
External width: 38.mm
Internal width: 27mm
Price: TBC
The new Terra Speed CLX III wheels weigh in at a claimed 1079 grams including valves and tape, which really is pretty impressive, and is a saving of at least a couple of hundred grams over the CLX II models. Roval says these wheels are for a blend of low weight and off-road comfort.
They feature a 27mm rim depth, and the same internal width as the Aero CLX, but they are 0.5mm narrower externally at 38mm.
These numbers make them shallower, yet wider internally and externally than the outgoing CLX II version. They have also received the carbon spoke treatment, which drops weight and boosts aero by a small amount.
Roval claims a 21.52% improvement in lateral compliance for comfort in harsh terrain, and the hooked bead is 4.86 mm wide.
There aren't any aero claims to pair with the Terra CLXIII's, but Roval claims it chose from 200 rim shapes through 'multi-factor modelling' to arrive at the new shape.
Gravel race equipment is evolving all the time, and we will see these wheels, in particular the Terra Aero, in use at the Traka and Unbound Gravel in just a few short months.
